Background: You are a herpetologist studying the pacific coast tree frog, Hyla r
ID: 11092 • Letter: B
Question
Background: You are a herpetologist studying the pacific coast tree frog, Hyla regilla. These frogs are typically green. However, a rare blue variant was recently discovered in Eureka (previously on display at the HSU Natural History Museum: http://now.humboldt.edu/news/rare-blue-frog-struts-its-stuff-at-nhm/). You have been studying these frogs for many years and have a true breeding “green strain” in captivity.You know that color is determined by special pigmented cells in the skin of the frog. “Green” results from production of blue or grey pigmentation and yellow pigment (blue plus yellow makes green). The blue-grey pigment is produced in the iridophore cells. The blue pigmentation filtered by yellow pigment production in the xanthophore cells to generate an overall green color. Hypoxanthism is a condition in which the yellow pigmentation is greatly reduced in the xanthophores. You suspect this to be the case in the blue frog discovered in Eureka.
A genetic screen in zebrafish identified 17 genes with mutations that disrupt expression yellow pigment. Some of these genes affect pigment production (the biosynthetic pathway for yellow pigment is non-functional), others affect the development of the xanthophore cells (no cells are produced so no yellow pigment can be made).
You decide to use this information and the molecular tools you learned of in BIOL340 genetics to identify the molecular basis of the blue color in this frog……
#2 Q:B. You determine the blue trait is recessive to green. You are interested in determining genetically whether the mutation in your blue frog is in a gene involved in xanthophore development or in yellow pigment production. Assume you have a yellow frog with a recessive mutation in the gene for blue pigment production. Knowing blue pigment + yellow pigment = green, describe a cross that will enable you to determine the mutation in your blue frog can complement the mutation in the yellow frog. Give the expected phenotypic results for each.
Explanation / Answer
Gathering from the text Dominant Recessive Green>Blue>Non-Blue Mutation 1 (cell produced but not pigment) Blue can be made but no yellow Mutation 2 (no cell and pigment does not matter) Non Blue (gray) frog produced Cross Blue Frog and Yellow Frog Blue pigment produced because Blue is dominant over non-blue recessive mutation. Assuming half show a green frog, the mutation 1 or 2 has to show a required complement.Related Questions
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